Shares in Countrywide, the UK's largest estate agent group, have fallen nearly 30% after it issued its second profit warning this year.
Countrywide, which has brands including Bairstow Eves and Gascoigne Pees, said it expected first-half earnings to be about £20m lower than last year.
"We do not expect this shortfall to be recovered in the second half," it said.
It said conditions in the housing market continued to be "subdued" and deals were taking longer to complete.
The firm has been hit by a slowdown in the housing market, as well as the rise of online agents such as Purplebricks.
Countrywide added that it was looking to raise "additional equity finance" with the aim of cutting debt by 50%.
Its share price fell 28% to 56.5p.
Chief executive Alison Platt left in January after the previous profit warning. Chairman Peter Long became executive chairman following her departure.
In March, shares slumped after the company announced that pre-tax profits for 2017 had more than halved to £25.2m, from £52.7m in 2016.
At the time, it said that it was shedding about 150 of its 450-strong head office team as part of a cost-cutting drive. The firm employs about 8,000 nationwide.
Countrywide is not the only estate agent to be suffering as the housing market hits tough times.
Earlier this year, another chain, Foxtons, reported a slump in profits as it warned that activity in the London housing market was near historic lows.
Foxtons said it expected "trading conditions to remain challenging during 2018", with sales anticipated to be lower than last year.
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